CN110212511B - 66kV arc suppression coil grounding system based on resistance remote automatic switching - Google Patents
66kV arc suppression coil grounding system based on resistance remote automatic switching Download PDFInfo
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- CN110212511B CN110212511B CN201910571947.0A CN201910571947A CN110212511B CN 110212511 B CN110212511 B CN 110212511B CN 201910571947 A CN201910571947 A CN 201910571947A CN 110212511 B CN110212511 B CN 110212511B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/08—Limitation or suppression of earth fault currents, e.g. Petersen coil
Abstract
The invention discloses a 66kV arc suppression coil grounding system based on resistance remote automatic switching, which comprises: the transformer substation comprises a 220kV transformer substation and a 66kV transformer substation which are connected through outgoing lines, wherein each 66kV outgoing line is provided with an outgoing line switch and a current transformer, a 66kV bus in the 220kV transformer substation is grounded after sequentially passing through a switching switch, a grounding transformer and a grounding resistor, a voltage transformer, a grounding resistor automatic switching controller and a line selection tripping device are further arranged in the 220kV transformer substation, the voltage transformer is used for monitoring the voltage of the 66kV bus, and the grounding resistor automatic switching controller and the line selection tripping device are respectively connected with the current transformer, the voltage transformer, the outgoing line switch and the switching switch. The 66kV arc suppression coil grounding system based on the remote automatic switching of the resistors can solve the problem caused by the exceeding of capacitance current without increasing the capacity of the arc suppression coil of the system and changing the grounding mode of the neutral point of the system.
Description
Technical Field
The invention relates to the technical field of automation of electric power systems, and particularly provides a 66kV arc suppression coil grounding system based on resistance remote automatic switching.
Background
A neutral point arc suppression coil grounding system is generally adopted in a 66kV power distribution network, under the grounding mode, no matter whether the system adopts an overhead line or a cable line, the protection is not tripped when a single-phase grounding fault occurs, and the system can operate for two hours with the fault. However, with the continuous development of urban power grid construction, the 66kV cabling rate is continuously improved, the system capacitance current level is greatly increased, and the arc suppression coil playing a role of compensating capacitance current cannot synchronously increase capacitance due to the limitation of the distribution device area, so that the compensation capacity of the arc suppression coil is insufficient, and the over-compensation mode is changed into the under-compensation mode, so that the arc is not easily extinguished, and the system resonance overvoltage is easily caused. In addition, most of single-phase earth faults of the cable line are permanent faults, interphase short-circuit faults are often caused by untimely fault treatment, even fire disasters occur in a cable tunnel, the accident range is enlarged, the accuracy of an earth selection device of an arc suppression coil earth system is not ideal, and the condition that the single-phase earth faults of the system exceed two hours but fault lines are not found out is often caused.
Therefore, it is a problem to be solved urgently to provide a novel 66kV arc suppression coil grounding system to realize automatic detection of single-phase ground fault and make corresponding treatment.
Disclosure of Invention
In view of this, the present invention provides a 66kV arc suppression coil grounding system and a single-phase grounding fault processing method based on resistance remote automatic switching, so as to solve the problem caused by the exceeding of the capacitance current of the arc suppression coil grounding system.
The invention provides a 66kV arc suppression coil grounding system based on resistance remote automatic switching, which comprises: the transformer substation comprises a 220kV transformer substation and a 66kV transformer substation, wherein main transformers in the 220kV transformer substation are both in Y-delta connection, no 66kV arc suppression coil is arranged in the substation, 66kV buses in the 220kV transformer substation are respectively connected with the 66kV transformer substation through 66kV outgoing lines, outgoing line switches and current transformers for detecting line currents are arranged on the 66kV outgoing lines, the 66kV buses are sequentially grounded through a switching switch, a grounding transformer and a grounding resistor, a voltage transformer, a grounding resistor automatic switching controller and a line selection tripping device are further arranged in the 220kV transformer substation, the voltage transformer is used for monitoring the voltage of the 66kV buses, the grounding resistor automatic switching controller and the line selection tripping device are respectively connected with the current transformers, the voltage transformers, the outgoing line switches and the switching switches and are used for controlling the switching of the switching switches according to the voltage values detected by the voltage, and controlling the tripping of the outgoing switch or sending an alarm signal to the outside according to the current value detected by the current transformer, wherein the 220kV transformer substation is connected with other 220kV transformer substations through 66kV connecting lines, and a 66kV arc suppression coil is installed in the 66kV transformer substation.
Preferably, the ground resistance automatic switching controller and the line selection tripping device are internally provided with tripping outlet hard pressing plates which correspond to the line outlet switches one by one, when the tripping outlet hard pressing plates are in a switching state, if a fault line is detected, the ground resistance automatic switching controller and the line selection tripping device trip off the line outlet switches corresponding to the tripping outlet hard pressing plates, and when the tripping outlet hard pressing plates are in a dividing state, if the fault line is detected, the ground resistance automatic switching controller and the line selection tripping device send out alarm signals to the outside.
Further preferably, the trip outlet hard pressing plate corresponding to the outlet switch on the 66kV connecting line is in a 'branch' state.
Further preferably, the rated thermal stability current of the grounding resistor is 2-4 times of the system single-phase grounding fault capacitance current, wherein the resistance value R of the grounding resistor is determined by the formula (1),
in the formula (I), the compound is shown in the specification,
for rating the system for phase voltage, IRIs the rated thermal stabilization current of the grounding resistor.
Further preferably, the ground resistor has a rated thermal stabilization current of 600A, 800A, 1000A or 1300A.
The invention also provides a method for processing single-phase earth faults by using the 66kV arc suppression coil grounding system based on the resistance remote automatic switching, which comprises the following steps: the voltage of a 66kV bus is monitored by using a voltage transformer, when the detected zero sequence voltage exceeds a preset setting value, a ground resistance automatic switching controller and a line selection tripping device control a switching switch to be closed, a ground resistance is put into the switching switch for a short time, the current amplitude, the resistive component and the zero sequence current of a fault line are obviously increased, the ground resistance automatic switching controller and the line selection tripping device can detect the fault line through the current transformer and trip a corresponding outlet switch or send an alarm signal to the outside.
The 66kV arc suppression coil grounding system based on the remote automatic switching of the resistors has the following beneficial effects:
(1) the single-phase earth fault current amplitude, the resistive component and the zero sequence current of the arc suppression coil grounding system are obviously increased by automatically inputting the grounding resistor in a short time, so that a single-phase earth fault circuit can be accurately selected, and the problem of low accuracy of the arc suppression coil grounding line selection is solved;
(2) the invention does not need to transform the original relay protection device of the transformer substation, can realize the selection and tripping of the fault line through the ground resistance automatic switching controller and the line selection tripping device, has low investment and obvious economic benefit;
(3) if the existing arc suppression coil grounding system is transformed into a resistance grounding system, a contact switch between substations needs to be disconnected during the transformation transition period so as to avoid the override trip of a relay protection device and be difficult to implement when being limited by the system operation mode.
The 66kV arc suppression coil grounding system based on the remote automatic switching of the resistors can solve the problem caused by the exceeding of the capacitance current without increasing the capacity of the arc suppression coil of the system and changing the grounding mode of the neutral point of the system, and can not cause the failure of the communication operation among the systems due to the inconsistent grounding modes of the neutral point of the system during the transformation transition period.
Drawings
The invention is described in further detail below with reference to the following figures and embodiments:
fig. 1 is a schematic structural diagram of a 66kV arc suppression coil grounding system based on resistance remote automatic switching provided by the invention.
Detailed Description
The invention will be further explained with reference to specific embodiments, without limiting the invention.
As shown in fig. 1, the invention provides a 66kV arc suppression coil grounding system based on resistance remote automatic switching, comprising: the transformer substation comprises a 220kV transformer substation 1 and a 66kV transformer substation 2, wherein main transformers in the 220kV transformer substation 1 are both Y-delta connection, no 66kV arc suppression coil is arranged in the substation, 66kV buses 11 in the 220kV transformer substation 1 are respectively connected with the 66kV transformer substation 2 through 66kV outgoing lines 3, outgoing line switches 31 and current transformers 32 used for detecting line currents are arranged on the 66kV outgoing lines 3, the 66kV buses 11 are grounded through switching switches 4, grounding transformers 5 and grounding resistors 6 in sequence, a voltage transformer 7, a grounding resistor automatic switching controller and a line selection tripping device 8 are further arranged in the 220kV transformer substation 1, the voltage transformer 7 is used for monitoring the voltage of the 66kV buses 11, the grounding resistor automatic switching controller and the line selection tripping device 8 are respectively connected with the current transformers 32, the voltage transformer 7, the outgoing line switches 31 and the switching switches 4, the transformer substation is used for controlling the on-off of the switching switch 4 according to the voltage value detected by the voltage transformer 7, controlling the tripping of the outgoing switch 31 or sending an alarm signal to the outside according to the current value detected by the current transformer 32, the 220kV transformer substation 1 is connected with other 220kV transformer substations 10 through a 66kV connecting line 9, and a 66kV arc suppression coil is installed in the 66kV transformer substation 2.
The 66kV arc suppression coil grounding system based on the resistance remote automatic switching can be transformed on the basis of the original 66kV arc suppression coil grounding system, the original 66kV arc suppression coils in a 66kV transformer substation can be completely worn, a fling-cut switch, a grounding transformer, a grounding resistor, an automatic grounding resistor fling-cut controller and a line selection tripping device are newly added on the 66kV side of a 220kV transformer substation main transformer (Y-delta connection) with an overproof capacitance current, the fling-cut switch is used for connecting a 66kV bus and the grounding transformer and realizing the fling-cut of the grounding transformer and the grounding resistor, the grounding transformer is used for leading out a 66kV neutral point of the main transformer, the connection of the neutral point of the transformer and the grounding resistor is realized, and the grounding transformerThe automatic switching controller of the resistance and the route selection tripping device are used for realizing the automatic switching and retreating of the grounding resistance and the route selection and tripping function of a fault line, and the functions are realized as follows: the device sets the automatic input function of the neutral point grounding resistor: when single-phase earth fault occurs, the zero-sequence voltage exceeds the setting value, the device is provided with a switching switch at the outlet, and a neutral point grounding resistor is put into the device; the device is provided with a neutral point grounding resistance automatic cutting function: the input time is suitable for meeting the fault line selection sampling requirement, generally less than 100ms, and when the input of the grounding resistor exceeds the preset setting time, the switching switch is disconnected at the outlet of the device, and the neutral point grounding resistor is withdrawn; the device is provided with a fault line selection tripping function: the device collects the three-phase current of each 66kV outgoing line branch in the station according to Ia+Ib+Ic＝3I0When a single-phase earth fault occurs in the system and the earth resistor is switched in, the amplitude value, the resistive component and the zero-sequence current of the fault current are obviously increased, so that the device can realize the accurate selection of the fault line according to the detection information of the current transformer.
When a 66kV line has a single-phase earth fault in a mode of operating in an arc suppression coil grounding mode for a long time, the fault characteristic component value can be remarkably improved by temporarily putting in a grounding resistor, and then the fault line is found and correspondingly processed. Because the original relay protection devices do not need to be replaced and modified and do not act on a single-phase earth fault, the original relay protection devices of all the substations do not malfunction, and the substations only provided with the earth resistors can realize fault line selection and tripping through the automatic ground resistor switching controllers and the line selection tripping devices, so that the problem that the substations cannot be in contact operation before the transformation transition period is solved.
As an improvement of the technical scheme, trip outlet hard pressure plates (not shown in the figure) which are in one-to-one correspondence with the outlet switches 31 are arranged in the ground resistance automatic switching controller and the line selection tripping device 8, so that an operator can select the tripping of a fault line or send an alarm signal, when the trip outlet hard pressure plates are in a 'throw' state, if the fault line is detected, the ground resistance automatic switching controller and the line selection tripping device 8 trip out the outlet switches 31 which correspond to the trip outlet hard pressure plates, and when the trip outlet hard pressure plates are in a 'branch' state, if the fault line is detected, the ground resistance automatic switching controller and the line selection tripping device 8 send an alarm signal to the outside.
As an improvement of the technical scheme, the trip outlet hard pressing plate corresponding to the outgoing line switch 31 on the 66kV connecting line 9 is in a 'separating' state.
The resistance value selection of the grounding resistor can comprehensively consider the technical requirements of relay protection, the influence of fault current on electrical equipment and communication, the influence on personal safety and system power supply reliability and the like, the resistance value and the thermal stability capacity of the resistor device need to be checked according to the operation mode of an installation area, short-circuit impedance and other parameters, as the improvement of the technical scheme, the rated thermal stability current of the grounding resistor 6 is 2-4 times of the single-phase grounding fault capacitance current of the system, wherein the resistance value R of the grounding resistor 6 is determined by a formula (1),
in the formula (I), the compound is shown in the specification,
for rating the system for phase voltage, IRIs the rated thermally stable current of the ground resistor 6.
As an improvement of the technical scheme, the rated thermal stabilization current of the grounding resistor 6 is 600A, 800A, 1000A or 1300A.
The invention also provides a method for processing single-phase earth faults by using the 66kV arc suppression coil grounding system based on the resistance remote automatic switching, which comprises the following steps: the voltage of a 66kV bus 11 is monitored by using a voltage transformer 7, when the detected zero sequence voltage exceeds a preset setting value, a ground resistance automatic switching controller and a line selection tripping device 8 control a switching switch 4 to be closed, a ground resistance 6 is switched in for a short time, the switching time is preferably less than 100ms, at the moment, the current amplitude, the resistive component and the zero sequence current of a fault line are obviously increased, the ground resistance automatic switching controller and the line selection tripping device 8 can detect the fault line through a current transformer 32, and trip out a corresponding outlet switch 31 or send an alarm signal to the outside.
The following respectively shows the processing process of the 66kV arc suppression coil grounding system with the resistance switched automatically in different places to the single-phase grounding fault when the 66kV outgoing line connected with the 66kV transformer substation in the grounding system provided by the invention has the single-phase grounding fault and the 66kV outgoing lines in other 220kV transformer substations connected with the grounding system provided by the invention have the single-phase grounding fault:
example 1
As shown in fig. 1, when a single-phase ground fault occurs in a 66kV outgoing line b of a 220kV substation 1, a voltage transformer of a 66kV bus of the 220kV substation 1 outputs a zero-sequence voltage, a ground resistance automatic switching controller and a line selection tripping device turn on a switching switch after a preset delay, and a ground resistance is put in, at this time, a fault current amplitude, a resistive component, and a zero-sequence current are all significantly increased, and the ground resistance automatic switching controller and the line selection tripping device can accurately select the outgoing line b as a fault line by collecting current values of respective loop current transformers. In the process, no special requirement is made on the operation mode of the system, and the line protection of other substations cannot be in misoperation and override trip.
Example 2
As shown in fig. 1, when a single-phase ground fault occurs in a 66kV outgoing line B in another 220kV substation 10 connected to a 220kV substation 1 through a 66kV interconnection line, if the 66kV interconnection line is in a closed state, the 66kV bus voltage transformer of the 220kV substation 1 outputs a zero-sequence voltage, the ground resistance automatic switching controller and the line selection tripping device turn on the switching switch after a preset delay, and put in a ground resistance, at this time, the fault current amplitude, the resistive component, and the zero-sequence current are all significantly increased, the ground resistance automatic switching controller and the line selection tripping device can select the interconnection line (outgoing line n) as a fault line by collecting the current value of each loop current transformer, wherein the trip outlet hard voltage plate corresponding to the outgoing line n is preferably in a "split" state, at this time, the ground resistance automatic switching controller and the line selection tripping device only send an alarm signal to the outside, and no tripping is performed. In the process, no special requirement is made on the operation mode of the system, and the line protection of other substations cannot be in misoperation and override trip. When the 220kV transformer substation 10 is also transformed into a 66kV arc suppression coil grounding system based on resistance remote automatic switching, the grounding resistance automatic switching controller and the line selection tripping device of the 220kV transformer substation 10 can accurately select the outgoing line B as a fault line.
The embodiments of the present invention have been written in a progressive manner with emphasis placed on the differences between the various embodiments, and similar elements may be found in relation to each other.
The embodiments of the present invention have been described in detail with reference to the drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.
Claims (6)
1. 66kV arc suppression coil grounding system based on different-place automatic switching of resistance, its characterized in that includes: the transformer substation comprises a 220kV transformer substation (1) and a 66kV transformer substation (2), wherein main transformers in the 220kV transformer substation (1) are Y-delta connection wires, no 66kV arc suppression coil is arranged in the substation, 66kV buses (11) in the 220kV transformer substation (1) are respectively connected with the 66kV transformer substation (2) through 66kV outgoing wires (3), outgoing switches (31) and current transformers (32) used for detecting line currents are arranged on the 66kV outgoing wires (3), the 66kV buses (11) are grounded after passing through switching switches (4), grounding transformers (5) and grounding resistors (6) in sequence, a voltage transformer (7), an automatic grounding resistor switching controller and a line selection tripping device (8) are further arranged in the 220kV transformer substation (1), the voltage transformer (7) is used for monitoring the voltage of the 66kV buses (11), and the automatic grounding resistor switching controller and the line selection tripping device (8) are respectively connected with the current transformers (32), The voltage transformer (7), the outgoing line switch (31) and the switching switch (4) are connected and used for controlling the switching switch (4) to be closed according to a voltage value detected by the voltage transformer (7) and controlling the outgoing line switch (31) to trip or send an alarm signal to the outside according to a current value detected by the current transformer (32), the 220kV transformer substation (1) is connected with other 220kV transformer substations through a 66kV connecting line (9), and a 66kV arc suppression coil is installed in the 66kV transformer substation (2).
2. The 66kV arc suppression coil grounding system based on resistive remote automatic switching according to claim 1, characterized in that: the automatic ground resistance switching controller and the line selection tripping device (8) are internally provided with tripping outlet hard pressing plates which correspond to the line outlet switches (31) one by one, when the tripping outlet hard pressing plates are in a switching state, if a fault line is detected, the automatic ground resistance switching controller and the line selection tripping device (8) trip out the line outlet switches (31) which correspond to the tripping outlet hard pressing plates, and when the tripping outlet hard pressing plates are in a dividing state, if the fault line is detected, the automatic ground resistance switching controller and the line selection tripping device (8) send alarm signals to the outside.
3. The 66kV arc suppression coil grounding system based on resistive remote automatic switching according to claim 2, characterized in that: and a tripping outlet hard pressing plate corresponding to the outlet switch (31) on the 66kV connecting line (9) is in a 'branch' state.
4. The 66kV arc suppression coil grounding system based on resistive remote automatic switching according to claim 1, characterized in that: the rated thermal stability current of the grounding resistor (6) is 2-4 times of the single-phase grounding fault capacitance current of the system, wherein the resistance value R of the grounding resistor (6) is determined by the formula (1),
in the formula (I), the compound is shown in the specification,
for rating the system for phase voltage, IRIs rated thermal stable current of a grounding resistor (6).
5. The 66kV arc suppression coil grounding system based on resistive remote automatic switching according to claim 4, characterized in that: the rated thermal stabilization current of the grounding resistor (6) is 600A, 800A, 1000A or 1300A.
6. The method for processing the single-phase earth fault by using the 66kV arc suppression coil grounding system based on the resistance remote automatic switching of any one of claims 1 to 5 is characterized in that: the voltage of a 66kV bus (11) is monitored by using a voltage transformer (7), when the detected zero sequence voltage exceeds a preset setting value, a ground resistance automatic switching controller and a line selection tripping device (8) control a switching switch (4) to be closed, a ground resistance (6) is put in for a short time, at the moment, the current amplitude, the resistive component and the zero sequence current of a fault line are obviously increased, the ground resistance automatic switching controller and the line selection tripping device (8) can detect the fault line through a current transformer (32), and trip out a corresponding outlet switch (31) or send an alarm signal to the outside.
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| CN103207352A (en) * | 2013-03-13 | 2013-07-17 | 福建省电力有限公司 | Method for achieving single-phase earth fault line selection of power distribution network by line selection impedance amplitude characteristic |
| CN106908693A (en) * | 2017-03-06 | 2017-06-30 | 国网浙江苍南县供电有限责任公司 | A kind of arc suppression coil earthing system single-phase grounding selecting method of high-accuracy |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103207352A (en) * | 2013-03-13 | 2013-07-17 | 福建省电力有限公司 | Method for achieving single-phase earth fault line selection of power distribution network by line selection impedance amplitude characteristic |
| CN106908693A (en) * | 2017-03-06 | 2017-06-30 | 国网浙江苍南县供电有限责任公司 | A kind of arc suppression coil earthing system single-phase grounding selecting method of high-accuracy |
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| 基于配电网柔性接地控制的故障消弧与馈线保护新原理;曾祥君等;《中国电机工程学报》;20120605;第32卷(第16期);第137-143页 * |
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